The present invention relates generally to agricultural round balers for forming round bales of cut crop material and twine wrapping systems that automatically wrap the formed bales with twine before expelling them onto a field for subsequent handling. More particularly, the invention relates to improvements in the bale wrapping system by providing four twine dispensing arms that result in a decrease in the amount of time it takes to wrap a formed bale with twine.
Typical round balers (also referred to simply as a xe2x80x9cbalerxe2x80x9d), such as disclosed in U.S. Pat. No. 6,209,450 to Naaktgeboren et al., are agricultural machines that pick up a cut crop material from the ground and form it into a compacted round bale in a bale forming chamber. When the bale has been sufficiently compacted to a desired density or a desired size depending on the baler construction, bale density or bale size sensors, as appropriate, send signals to a controller that subsequently sends a signal to an operator""s panel to stop forward motion of the baler so that a bale wrapping operation can be performed, wherein the formed bale is wrapped with netting or twine to produce a completed wrapped bale.
Typically, the wrapping operation is performed by a bale wrapping mechanism controlled by a bale wrapping algorithm preprogrammed into a controller (i.e., microprocessor) that is part of the baler. In the prior art baler of the present assignee, the bale wrapping mechanism has two twine wrapping tubes/arms, wherein each tube/arm dispenses a single strand of twine. When a wrap cycle is initiated, the twine tubes/arms are moved arcuately to an extended or insert position with an end of each respective twine strand dangling from the end of the corresponding twine tube/arm; optionally, a pusher mechanism, often referred to as a xe2x80x9cduckbill,xe2x80x9d is actuated to move the dangling twine ends toward the formed bale so that the ends of the twine strands are adjacent to the bale near its lengthwise middle. Subsequently, the dangling strands are caught by the cut crop material of the rotating bale as it rotates in the bale forming chamber so that the twine is pulled from the twine tubes/arms and wraps around the bale as the bale continues to rotate. As twine is pulled from the twine tubes/arms and wraps about the rotating bale, the twine tubes/arms are moved from the middle to the ends of the bale so that twine wraps all along the length of the bale. At the end of a wrap cycle, a tying operation is performed as is generally known. Before the completed wrapped bale is expelled from the baler, the twine strands must be cut, then the baler tailgate opens and the completed wrapped bale is expelled from the baler to the ground.
However, there are two problems with the assignee""s prior bale wrapping apparatus having two twine tubes/arms. First, during the wrapping operation, each twine tube/arm is moved across a portion of the width of the rotating surface of the bale in a prescribed fashion to control the position of the twine on the bale to provide a secure wrap, then at least two wraps are required with the tubes/arms stationary at the beginning and the end of the wrapping cycle in order to effectively tie the bale securely. The problem with this system is that it takes an excessive amount of time to wrap a bale. Second, when applying twine to the bale, the two twine tubes/arms move to a starting position to insert twine into the bale forming chamber, then the tubes/arms gradually move back to a home position to finish wrapping the bale. As twine is applied to the bale, tension must be applied to the twine to ensure that the bale is tied securely. While twine tension helps in securing the bale, it is detrimental to starting the twine wrapping cycle. For this reason, it would be advantageous to have a mechanism that places low tension on the twine as it starts to wrap on the bale, then increases tension on the twine after the twine has started wrapping about the bale.
The present invention endeavors to provide a round baler with an improved bale wrapping apparatus with four twine tubes on two twine dispensing arms to facilitate the rapid wrapping of a formed bale. Furthermore, the present invention will provide structure that provides low tension in the twine at the beginning of a wrap cycle and that provides greater tension in the twine once the wrap cycle had progressed.
Accordingly, one object of the present invention is to overcome the disadvantages of the assignee""s prior bale wrapping apparatuses having two twine tubes/arms (i.e., one twine tube per arm).
Another object of the present invention is to provide a bale wrapping apparatus that achieves the wrapping and tying of a formed bale in less time than the prior devices, thereby shortening the time to complete a bale wrapping cycle by 40-50%.
Another object of the present invention is to provide a bale wrapping apparatus that automatically adjusts the tension in the twine so that there is low tension in the twine at the beginning of a wrap cycle and higher tension in the twine after the beginning of a wrap cycle.
Another object of the present invention is to provide a bale wrapping apparatus that keeps four twine strands more evenly spaced across the surface of a bale during a bale wrapping operation.
Another object of the present invention is to provide a bale wrapping apparatus that is practical and cost effective to manufacture.
Another object of the present invention is to provide a bale wrapping apparatus that is both durable and reliable, and easy to maintain.
In accordance with the above objectives, a first preferred embodiment of the present invention provides a round baler comprising: (a) a housing; (b) a bale chamber defined in part by walls of the housing and having an opening for receiving a cut crop material; (c) a bale forming apparatus defining at least a portion of the bale chamber, configured to form a rotating bale of cut crop material in the chamber, and disposed inside the housing; (d) a bale wrapping apparatus disposed near the bale chamber to wrap a rotating bale formed in the chamber: (e) four twine supply rolls rotatingly connected to the housing and defining four twine strands; (f) four twine dispensing tubes, wherein each dispensing tube presents a corresponding one of the four twine strands so that an end of each strand dangles from the corresponding tube, each tube being movable between (1) a home position and (2) a twine insert position, wherein each twine strand end dangles adjacent to a position of a bale rotating in the chamber when the four dispensing tubes are in the twine insert position; and (g) two twine tensioning members disposed so that each twine tensioning member receives two of the four twine strands, wherein each twine tensioning member has a receiving portion through which the two strands are threaded, wherein each twine tensioning member is positioned to provide slack tension on the ends of the respective two strands when the four dispensing tubes are in the twine insert position, and wherein each twine tensioning member is positioned to increase wrapping tension on the respective two strands after the respective two strands have started to wrap the rotating bale.
In accordance with a second preferred embodiment of the present invention, the first preferred embodiment is further modified so that each twine tensioning member has two holes formed therein to provide the receiving portion and wherein each hole receives threaded therethrough one of the respective two strands.
In accordance with a third preferred embodiment of the present invention, the first preferred embodiment is further modified so that each twine dispensing tube is provided by a tube or a ring through which a respective one of the four strands is threaded therethrough.
In accordance with a fourth preferred embodiment of the present invention, the first preferred embodiment is further modified so that each twine dispensing tube is movable along an arcuate path between the home position and the twine insert position.
In accordance with a fifth preferred embodiment of the present invention, the first preferred embodiment is further modified so that the bale wrapping apparatus further comprises two arm members, each arm member being connected to a respective two of the four twine dispensing tubes.
In accordance with a sixth preferred embodiment of the present invention, the first preferred embodiment is further modified so that each arm member includes two hollow portions through which a respective one of the four twine strands passes.
In accordance with a seventh preferred embodiment of the present invention, the fifth preferred embodiment is further modified so that the bale wrapping apparatus further comprises a twine arm pivotally connected at one end to a cam member connected to each arm member and pivotally connected at the other end to a base mount.
In accordance with an eighth preferred embodiment of the present invention, the seventh preferred embodiment is further modified so that each twine tensioning member is provided by a portion of the base mount.
In accordance with a ninth preferred embodiment of the present invention, the seventh preferred embodiment is further modified so that each twine arm is provided by two link members, each link member being pivotally connected at one end to a respective cam member and pivotally connected at the other end to the base mount.
In accordance with a tenth preferred embodiment of the present invention, the ninth preferred embodiment is further modified so that each link member has a hollow portion and one of the four twine strands is threaded through the hollow portion of each link member.
In accordance with an eleventh preferred embodiment of the present invention, the first preferred embodiment is further modified so that each twine dispensing tube is movable to a cutting position, and wherein each twine tensioning member provides additional tension to each of the respective two strands when the four twine dispensing tubes are in the cutting position.
Further objects, features and advantages of the present invention will become apparent from the Detailed Description of Preferred Embodiments, which follows, when considered together with the attached drawings.